This invention relates to a DC-AC converter for supplying a gas and/or vapour discharge lamp, which converter has two input terminals which are connected together by means of a series arrangement of at least two semiconductor switching elements provided with a control circuit, one of the semiconductor switching elements constituting a circuit with a series arrangement of at least a capacitor, the lamp and an inductance in the operating condition of the lamp. The electric arrangement is provided with two rectifiers. An alternating current flows through the lamp in the operating condition, said current, plotted against time, having at least approximately a square-shaped variation.
A known DC-AC converter of this type is described, for example, in EP No. 63,284 (FIG. 8). The undimmed lamp situation is concerned in this case. In this known converter the semiconductor switching elements alternately convey the lamp current in the operating condition.
A drawback of this known converter is that a third semiconductor switching element is present which also conveys the lamp current in the operating condition. This additional switching element connected in the circuit through which the lamp current flows makes this DC-AC converter complicated.